title: Blood flow to the scarred gravid uterus at 22-24 weeks of gestation.
abstract: OBJECTIVE
  To compare uterine artery volume blood flow (Q(uta)), vascular resistance (R(uta)), pulsatility index (Uta PI), and the fraction of maternal cardiac output (CO) distributed to the uteroplacental circulation in pregnant women with and without a previous caesarean section.
  
  
  METHODS
  Cross-sectional observational study.
  
  
  METHODS
  University hospital in Norway.
  
  
  METHODS
  Thirty-two pregnant women with previous caesarean section and 32 matched controls.
  
  
  METHODS
  Ultrasonography was used to measure uterine artery diameter and blood flow velocity between 22(+0) and 23(+6) weeks of gestation. Impedance cardiography was used to assess maternal haemodynamics.
  
  
  METHODS
  Q(uta), R(uta), Uta PI, and the fraction of maternal CO distributed to the uteroplacental circulation.
  
  
  RESULTS
  The mean Q(uta) was 356.26 ± 213.72 ml/minute in cases and 456.41 ± 209.70 ml/minute in controls (P = 0.038). R(uta) was significantly (P = 0.026) higher among cases compared with controls (0.32 ± 0.20 versus 0.22 ± 0.14 mmHg/ml/minute), but the Uta PI did not differ between the groups (0.93 ± 0.23 versus 0.92 ± 0.47; P = 0.929). The fraction of maternal CO distributed to the uteroplacental circulation was 5.75 ± 3.68% in cases and 8.45 ± 5.02% in controls (P = 0.014).
  
  
  CONCLUSIONS
  Uterine artery volume blood flow and the fraction of maternal cardiac output distributed to the uteroplacental circulation are lower, and uterine vascular resistance (but not Uta PI) is higher, in women with previous caesarean section compared with the control group.
authors.affiliation: Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway; Department of Obstetrics and Gynaecology, University Hospital of North Norway, Tromsø, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Flo
authors.forename: C
authors.initials: C
authors.lastname: Widnes
authors.forename: Å
authors.initials: Å
authors.lastname: Vårtun
authors.forename: G
authors.initials: G
authors.lastname: Acharya
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D002307:Cardiography, Impedance; D016022:Case-Control Studies; D002921:Cicatrix / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D020073:Gravidity; D006801:Humans; D021041:Placental Circulation / Q000502:physiology*; D011247:Pregnancy; D011673:Pulsatile Flow / Q000502:physiology; D018608:Ultrasonography, Doppler; D055988:Uterine Artery / Q000000981:diagnostic imaging; D014599:Uterus / Q000098:blood supply* / Q000293:injuries*; D014655:Vascular Resistance / Q000502:physiology
keywords: Maternal haemodynamics; previous caesarean section; uterine artery Doppler; uterine artery blood flow